Skip to content

Configuring images for update

Annotation format

You can specify one or more image(s) for each application that should be considered for updates. To specify those images, the following annotation is used: <image_spec_list>

The <image_spec_list> is a comma separated list of image specifications. Each image specification is composed of mandatory and optional information, and is used to specify the image, its version constraint and a few meta data.

An image specification could be formally described as:


Specifying the fields denoted in square brackets is optional and can be left out.

Allowing an image for update

The most simple form of specifying an image allowed to update would be the following: nginx

The above example would specify to update the image nginx to it's most recent version found in the container registry, without taking any version constraints into consideration.

This is most likely not what you want, because you could pull in some breaking changes when nginx releases a new major version and the image gets updated. So you can give a version constraint along with the image specification: nginx:~1.26

The above example would allow the nginx image to be updated to any patch version within the 1.26 minor release.

More information on how to specify semantic version constraints can be found in the documentation of the Semver library we're using.


If you use an update strategy other than semver, the version_constraint will not be have any effect and all tags returned from the registry will be considered for update. If you need to further restrict the list of tags to consider, see filtering tags below.

Assigning aliases to images

It's possible (and sometimes necessary) to assign an alias name to any given image. Alias names should consist of alphanumerical characters only, and must be unique within the same application. Re-using an alias name across different applications is allowed.

An alias name is assigned during image specification in the image-list annotation, for example the following would assign the alias myalias to the image some/image: myalias=some/image

Assigning an alias name to an image is necessary in these scenarios:

  • If you want to use custom images with Kustomize. In this case, the name must match to what is defined in your Kustomize base.

  • If you need to specify the Helm parameters used for rendering the image name and version using Helm and the parameter names do not equal and image.tag. In this case, the name is just symbolic.

  • If you want to set custom options for a given image's update strategy, or require referencing unique pull secrets for each image

The alias you assign to any image will be reused as a key in the annotations used to define further options, so a little care should be taken when defining such a name. It's generally advised to use only alpha-numerical characters. The character / (forward-slash) can be used in the name, but must be referenced as _ (underscore) in the annotation. This is a limit of Kubernetes. So for example, if you assign the alias argoproj/argocd to your image, the appropriate key in the annotation would be referenced as argoproj_argocd.

Update strategies

Argo CD Image Updater can update images according to the following strategies:

Strategy Description
semver Update to the tag with the highest allowed semantic version
latest Update to the tag with the most recent creation date
name Update to the tag with the latest entry from an alphabetically sorted list

You can define the update strategy for each image independently by setting the following annotation to an appropriate value:<image_name>.update-strategy: <strategy>

If no update strategy is given, or an invalid value was used, the default strategy semver will be used.


As of November 2020, Docker Hub has introduced pull limits for accounts on the free plan and unauthenticated requests. The latest update strategy will perform manifest pulls for determining the most recently pushed tags, and these will count into your pull limits. So unless you are not affected by these pull limits, it is not recommended to use the latest update strategy with images hosted on Docker Hub.

Filtering tags

You can specify an expression that is matched against each tag returned from the registry. On a positive match, the tag will be included in the list of tags that will be considered to update the image to. If the expression does not match the tag, the tag will not be included in the list. This allows you to only consider tags that you are generally interested in.

You can define a tag filter by using the following annotation:<image_name>.allow-tags: <match_func>

The following match functions are currently available:

Function Description
regexp:<expression> Matches the tag name against the regular expression <expression>
any Will match any tag

If you specify an invalid match function, or the match function is misconfigured (i.e. an invalid regular expression is supplied), no tag will be matched at all to prevent considering (and possibly update to) the wrong tags by accident.

If the annotation is not specified, a match function any will be used to match the tag names, effectively performing no filtering at all.

Ignoring certain tags

If you want to ignore certain tags from the registry for any given image, you can define a comma separated list of glob-like patterns using the following annotation:<image_name>.ignore-tags: <pattern1>[, <pattern2>, ...]

You can use glob patterns as described in this documentation

If you want to disable updating an image temporarily, without removing all of the configuration, you can do so by just ignoring all tags, effectively preventing the image updater to consider any of the tags returned from the registry:<image_name>.ignore-tags: "*"

Please note that regular expressions are not supported to be used for patterns.

Specifying pull secrets

There are generally two ways on how to specify pull secrets for Argo CD Image Updater to use. Either you configure a secret reference globally for the container registry (as described here), or you can specify the pull secret to use for a given image using the annotation<image_name>.pull-secret: <secret_ref>

A configuration for an image will override what is configured for the registry, for that certain image.

The secret_ref can either be a reference to a secret or a reference to an environment variable. If a secret is referenced, the secret must exist in the cluster where Argo CD Image Updater is running in (or has access to).

Valid values for secret_ref are:

  • secret:<namespace>/<secret_name>#<field> - Use credentials stored in the field field from secret secret_name in namespace namespace.

  • pullsecret:<namespace>/<secret_name> - Use credentials stored in the secret secret_name in namespace namespace. The secret is treated as Docker pull secret, that is, it must have a valid Docker config in JSON format in the field .dockerconfigjson.

  • env:<variable_name> - Use credentials supplied by the environment variable named variable_name. This can be a variable that is i.e. bound from a secret within your pod spec.

  • ext:<path_to_script> - Use credentials generated by a script. The script to execute must be specified using an absolute path, and must have the executable bit set. The script is supposed to output the credentials to be used as a single line to stdout, in the format <username>:<password>. Please note that the script will be executed every time Argo CD Image Updater goes to find a new version, and credentials will not be cached. If you want it to execute only once and cache credentials, you should configure this secret on the registry level instead.

In case of secret or envreferences, the data stored in the reference must be in format <username>:<password>

Custom images with Kustomize

In Kustomize, if you want to use an image from another registry or a completely different image than what is specified in the manifests, you can give the image specification as follows:


<image_name> will be the original image name, as used in your manifests, and <image_path>:<image_path> will be the value used when rendering the manifests.

Let's take Argo CD's Kustomize base as an example: The original image used by Argo CD is argoproj/argocd, pulled from the Docker Hub container registry. If you are about to follow the latest builds, as published on the GitHub registry, you could override the image specification in Kustomize as follows:


Specifying Helm parameter names

In case of Helm applications which contain more than one image in the manifests or use another set of parameters than and image.tag to define which image to render in the manifests, you need to set an <image_alias> in the image specification to define an alias for that image, and then use another set of annotations to specify the appropriate parameter names that should get set if an image gets updated.

For example, if you have an image that is configured in your helm chart using the and dex.image.tag Helm parameters, you can set the following annotations on your Application resource so that Argo CD Image Updater will know which Helm parameters to set: dex.image.tag

The general syntax for the two Helm specific annotations is:<image_alias>.helm.image-name: <name of helm parameter to set for the image name><image_alias>.helm.image-tag: <name of helm parameter to set for the image tag>

If the chart uses a parameter for the canonical name of the image (i.e. image name and tag combined), a third option can be used:<image_alias>.helm.image-spec: <name of helm parameter to set for canonical name of image>

If the <image_alias>.helm.image-spec annotation is set, the two other annotations <image_alias>.helm.image-name and <image_alias>.helm.image-tag will be ignored.


Following an image's patch branch

Scenario: You have deployed image nginx:1.19.1 and want to make sure it's always up-to-date to the latest patch level within the 1.19 branch.

Solution: Use standard semver update strategy with a constraint on the patch level (~), i.e. nginx:~1.19

Always deploy the latest build

Scenario: Your CI regularly pushes images built from the latest source, using some identifier (i.e. the hash of the Git commit) in the tag.


  1. Give your image a proper alias, i.e. yourtool and do not define a version constraint.

  2. Use latest as update strategy

  3. If you just want to consider a given set of tags, i.e. v1.0.0-<hash>, use a allow-tags annotation.

Annotations might look like follows: yourtool=yourorg/yourimage latest regexp:^v1.0.0-[0-9a-zA-Z]+$

Multiple images in the same Helm chart

Scenario: You want to update multiple images within the same Helm chart to their latest available version according to semver.

The Helm parameters to set the image version are foo.image and foo.tag for the first image, and bar.image and bar.tag for the second image. The image names are foo/bar and bar/foo for simplicity.


  1. Define an alias for both images, i.e. fooalias and baralias

  2. Set helm.image-name and helm.image-tag for both aliases to their appropriate values

Annotations might look like follows: fooalias=foo/bar, baralias=bar/foo foo.image foo.tag bar.image bar.tag


Available annotations

The following is a complete list of available annotations to control the update strategy and set options for images. Please note, all annotations must be prefixed with

Annotation name Default value Description
image-list none Comma separated list of images to consider for update
<image_alias>.update-strategy semver The update strategy to be used for the image
<image_alias>.allow-tags any A function to match tag names from registry against to be considered for update
<image_alias>.ignore-tags none A comma-separated list of glob patterns that when match ignore a certain tag from the registry
<image_alias>.pull-secret none A reference to a secret to be used as registry credentials for this image
<image_alias>.helm.image-spec none Name of the Helm parameter to specify the canonical name of the image, i.e. holds image/name:1.0. If this is set, other Helm parameter related options will be ignored.
<image_alias>.helm.image-name Name of the Helm parameter used for specifying the image name, i.e. holds image/name
<image_alias>.helm.image-tag image.tag Name of the Helm parameter used for specifying the image tag, i.e. holds 1.0
<image_alias>.kustomize.image-name original name of image Name of Kustomize image parameter to set during updates